A known type of hydraulic braking pressure control apparatus for an automotive vehicle is described in Japanese Patent Laid-Open Patent Application No. 8-11696. The hydraulic braking pressure control apparatus is of the type that includes a master cylinder integrally provided with an ABS actuator or both an ABS actuator and a TRC actuator. In this conventional braking pressure control apparatus, all the component parts of the actuators including the reservoir, the pump motor and the pump body are integrally assembled with the cylinder body of the master cylinder or are separately mounted on the cylinder body of the master cylinder. The pump motor in particular is mounted on the cylinder body sideways.
This type of conventional hydraulic braking pressure control apparatus suffers from a variety of drawbacks and disadvantages. In one respect, when the actuator assembly is mounted on the cylinder body of the master cylinder, a relatively large space is occupied by the actuator assembly. This makes the overall size of the hydraulic braking pressure control apparatus undesirably large. In addition, the center of gravity of the control apparatus is shifted to one side due to the weight of the actuator assemblies and the pump motor. As a result, difficulties arise in mounting the control apparatus to a vehicle body structure. Additionally, a firm support structure is required to support the control apparatus and prevent vibration. Further, if the component parts of the actuator are separately mounted on the cylinder body of the master cylinder, it is necessary to provide mounting portions on the cylinder body for the respective component parts. This means that different kinds of cylinder bodies are required to accommodate different kinds of actuators, thus undesirably increasing the cost associated with manufacturing the hydraulic braking pressure control apparatus.